Process of manufacturing manhole covers



April 2 1929- A. E. ALLlsoN PRQCESS OF MANUFACTURING MANHOLE COVERS Filed nec, 1v,A 1927 2 Sheets-Sheet W//f//W/ .Uy/ Y April 2, 1929. A. E. ALLlsoN Pnocsss or umumcwumc, mmol.: comas Filed DC- 17. 1927 2 Sheets-Sheet 2 Imam A rME/WZLSm /fwwfn M Patented Apr. k2, 1929.

1,701,891-, UNITEDv )STATES PATENT OFFICE.

ARTHUR E. ALLIsoN, or coATEsVvILLE, PENNSYLVANIA, AssIGNoB. To WORTH STEEL COMPANY, or CLAYMONT, DELAWARE, A coEPoRA'rIoN or DELAWARE.

PROCESS MANUFACTURING HANIHOLE COVERS.

Application filed December 17, 1927. Serial No. 240,743.

y invention relates to certain improvements in the process of making manhole covers, such as illustrated in application for patent filed by me on the second day of December, 1927, under Serial No. 237,238.

The object of my present invention. 1s to simplify the method of manufacturing a manhole cover, in which a bolt-receiving plate is secured firmly in place in the manhole cover.

In the accompanying drawings:

Figure Y 1 is a sectional view of a press, showing the first step in the process of making the manhole cover plate;

Fig. 2 isa view similar to Fig. 1, with certain parts removed, showing the second step in the process; f

Fig. 3 is a view similar to Fig. 2, showing the third step in the process, namely, forming the flange andthat portion. which is turned over to retain the bolt-receiving plate in position;

Fig. 4 is a View showing the sectional dies for finishing the pressing operation illustrated in Fig. 3; l

Fig. 5 is a view showing the dies for pressing the body portion of the cover plate over the bolt-receiving plate which is placed in position at this step in the process ;A

Fig. 6 is a view showing the completion of the operation, the dies having pressed the body portion of the manhole cover over the bolt-receiving plate so as to retain the plate in the cover;

Fig. 7 is a plan view of a cover plate made in accordance with my invention;

Fig. 8 is a longitudinal sectional view on the line S3 of Fig. 7, and

Fig. 9 is a transverse sectional view on the line 9 9 of Fig. 7.

Referring to Figs. 7 and 8, 1 is the manhole cover having a flange 7. This cover is depressed at the center as at. 3 for the reception of the bolt-receiving plate 4. The cover is further depressed as at 5 for the heads of the securing bolts. The bolts extend through openings 6 in the plate 4, the openings being wider at one point than at another to allow for the insertion of the heads of the bolts.

The body portion'2 of the manhole cover is pressed so as to overlap the bolt-receiving plate as clearly shown in Fig. 8, and the process which I will now proceed to describe refers to the method of shaping the manhole cover plate so as to retain the bolt-receiving plate in a fixed position in said cover. In i the first place, the manhole cover is made from a flatplate and inserted between the dies shown in Fig. 1.

10 is a base carrying alower fixed die, and in the fixed die 11 is a movable die 12 having a projection 13 which forms the depression 5 in themanhole cover plate.

14 is the upper die having a projection 15 beveled at its lower edge. This projection eventually forms the bend in the body portion 2. Within the upper die 14 is a movable die 16 havin a recess 17 forthe reception of the metal ofg the blank which is forced into shape by the movable lower die 12. After the metal has been shaped, as shown in Fig. 1, the movable lower die 12 is forced up into the fixed die 14, the projection portion 15 of the upper die holding the main portion of the blank upon the fixed lower die l1.

The movable upper die 16 recedes as the lower die is projected. This movement shapes the metal of the manhole cover so as to form the recess 3 for the bolt-receiving Y plate 4.

In Fig. 3 the upper die 14 has been forced down with the movable upper die 16, so as to form the rounded body portion 2 of the manhole cover and also to initially shape the fiange 7. Y

The cover plate is now in sha e to receive the bolt-receiving plate 4 which) is set into the recess 3, as shown in Fig. 5, and a die 18 is used to hold the fiange firmly in position, while a lnovable upper die 19. having a beveled surface 20, is used to force the body` portion- 2 of the manhole cover towards the center, causing it to overlap to a certain extent the bolt-receiving plate 2. Then per dies 18 and 19 are then removed and the die 21 is lowered into position as shown in Fig. 6, and as it is. lowered it presses the body portion so that it extends over the edge of the bolt-receivingplate and holds it firmly in position.` This operation completes the formation of the manhole cover plate.

I claim:

The process herein described of making a manhole cover with a bolt-receiving plate retained therein, said process consisting in the pressing of a blank for the manhole cover to form a depression for the heads of securing bolts by means of a lower die; then continuing the operation by projecting the lower die into an upper die to-make a further depres- 2 n e iper/,sei

sion inthe blank for 4the reception of tlllevholt-I reeelvmg .plate then lowel-mg im uppel' die hevmgi a projeetmg portlon Whleh shgpeg fughe bodT of the manhole cover blank; plaeing V@he bolt-'receiving Vplete ih position in che i'eeesfs formed by the lo'wer die; then, by the hse of 'a beveled upper die, forcing the lhetaloftlle manhole @over over the bolt-receiving plate;

arid finally red ,portion of the seid manhole cover by Vpess- 10 uong the height of the body A111e' 11@ bodyperten @the manhole .www eauvsm-g '1t to extend ovel' the edge of 'the holt- ARTHUR E. ALLSoN. 

